Mostly because LBJ stans are working overtime to overrate the record.
To be honest, the record doesn't mean much to me. It shouldn't really move the meter for anyone who understands Lebron's greatness. The fact is that he's played at an elite level for a longer period of time than any other player in history. When it comes to longevity, he's the king, and it's not even close. There's really no debating that. I mean Kareem had the record, but a lot of that was stat padding and playing long past his prime. Lebron hasn't done that. He's been great from year one and is still an All Star top tier player in year 18. To me, Lebron would have been just as great if he retired last year and never passed Kareem.
I think the MJ vs Lebron argument is fun but overdone, and I'm sure you're right that the super MJ fanboys are doing all kinds of damage control. But they are doing that in response to the LBJ fanboys acting like breaking this record ends the argument about who's the greatest. To me that's stupid. Bulk numbers are about longevity, and like I said, Lebron was already the longevity king, so it doesn't mean anything as far as that debate goes. If you're someone who thinks longevity is all that matters, you probably already thought LBJ was the GOAT. If you're someone that factors other requirements into GOAT status, then whether you think Lebron is the GOAT or not, him breaking the record is not going to change your mind.